The objectives of the study were to evaluate push out bond strength of FRC posts luted with different resin cement systems, to investigate the effect of root canal surface treatments before FRC posts luted with self adhesive resin cement and compare different root regions on push out bond strength. Sixty single-rooted mandibular premolars were randomly divided in six groups (n=10), decoronated, endodontically treated and prepared post spaces for Fibrekleer® no.3. Root canal surfaces were treated as follows, group 1; applied Excite® DSC and Variolink®II. Group 2; applied ED primer II and Panavia™F 2.0. Group 3; applied RelyX™Unicem. Group 4-6; root canal surfaces were treated before before posts were luted with RelyX™Unicem, with 37% H3PO4 for 5 s, 17% EDTA for 60 s, and 17% EDTA for 60 s +2.5% NaOCl for 15 s, respectively. Each root was sectioned to 6 slices, each 1±0.05 mm thickness to represent the coronal, middle and apical regions. Push out tests were performed by an Instron® machine at a crosshead speed of 0.5 mm/min. Data were analyzed by two-way ANOVA and Tukey test at P<0.05. Every specimen were evaluated for modes of failure. The results showed that bond strength was significantly affected by root regions only in group 1(P<0.05). Push out bond strength of group 1 in coronal region was higher than group 2 and 3 for all regions (P<0.05). The bond strength of group 1 in middle region was higher than group 2 but not different from group 3 for all regions (P>0.05). Push out bond strengths of group 1-3 in apical region were not significantly different (P>0.05). Moreover, push out bond strength of group 4 was significantly higher than group 3, 5 ,and 6 (P<0.05). Whereas, there was no significant difference between group 3 and 6 (P>0.05).
